In the typical ultrasonic system such as used for inspection of metal parts to detect internal defects therein, bursts of ultrasonic energy are transmitted from a transducer into a part while a horizontal sweep signal is applied to a cathode ray tube, with echo signals being effective to produce vertical deflections or "pips" on the screen of the cathode ray tube, a "A" scan arrangement being used. In many inspection operations, it is very difficult for the inspector to keep his attention and concentration and avoid fatigue. In the inspection of welded seams of pipe, it has been found that it helps to move the transducer toward and away from the weld zone with a "scrubbing" action, the result being movement of the echo indications which is easier to detect visually than stationary indications. Even so, however, the inspector must use a great deal of concentration and attention to avoid missing of defects and potential defects during the inspection operation.